PROBLEMS OF DISTRIBUTION AND THEIR SOLUTION. 177 



over the surface of the globe. Thus the lemurs have their head- 

 quarters in Madagascar, as already remarked, but they also occur in 

 the Eastern Archipelago. They are scattered, to use the words ot 

 Mr. Wallace, " from Sierra Leone to Celebes, and from Natal to 

 Eastern Bengal and South China." How, it may be asked, can the 

 apparently erratic nature of the distribution of these animals be 

 accounted for ? and how can the facts of such a straggling population 

 be harmonised with those conceptions of orderly biological and 

 physical laws on which the science of distribution bases its existence ? 

 Mr. Sclater himself, in 1864, postulated the former existence 

 of a continent occupying the site of the existing Indian Ocean. 

 This continent, named Lemuria, he conceived might have formed 

 the headquarters of the lemur group, whence they became radiated 

 and dispersed east and west. Such an hypothesis is no longer 

 required, however, to account for the curious distribution of 

 the lemurs. In the light of new facts, and especially in the face 

 of geological evidence, the existence of the theoretical " Lemuria " 

 is rendered unnecessary. Mr. Sclater's perfectly justifiable sup- 

 position has simply been superseded by more natural explanations 

 of the distribution of the lemurs, whilst the views entertained 

 regarding the permanence of the great ocean basins and of the 

 continental land areas are likewise opposed to the theory of a 

 former land-connection between the Ethiopian and Oriental ter- 

 ritories. For what are the geological facts concerning the range of 

 the lemurs in the past ? Their fossil remains occur in the Eocene 

 rocks of France that is, in the lowest and oldest of the Tertiary 

 deposits the remains in question being those of a form allied to 

 the existing " potto" of West Africa ; and in North America, where 

 the lemurs exist to-day, the Lower Eocene rocks afford evidence 

 of their existence in the past of the New World. So that we find at 

 the outset our difficulties largely resolved by the bare mention of 

 the idea that the existing anomalies in the range of the lemurs 

 really depend upon their past history. In a word, as the "Marsupial " 

 population of Australia is to be regarded as a survival, owing to land 

 separation, of an animal class once world-wide in its range, so the 

 lemurs now found at distant points in Africa and Asia, are merely 

 the survivals of a lemurine family circle once represented both in 

 the Old World and in the New. We know of their existence in 

 Eocene times in Europe, and thence they probably spread in all 

 directions to Africa, Madagascar, Asia, and elsewhere. Killed off 

 over the general area inhabited by their race, the lemurs have re- 

 mained in the environs of the earth, so to speak, because there, to 

 this day, the competition with higher forms is not too severe. Like 

 the American opossums, the lemurs represent to-day the mere 

 remnants of a once world-wide class. Their distribution has not 



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